In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress ...In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress and spring back of the spiral plate were calculated. Relationships between the spiral pitch to inclination angle of the punch and die, material properties and thickness of the plate were analyzed. A data converter was developed and effectively used in the analysis. The results of FEM analysis and simulation have been applied to design the spiral plate forming machines.展开更多
This paper presents a method to study the free vibration of a plate with circular holes.The circular hole is regarded as a virtual small plate in which the mass density and Young's modulus are zero.Therefore,the f...This paper presents a method to study the free vibration of a plate with circular holes.The circular hole is regarded as a virtual small plate in which the mass density and Young's modulus are zero.Therefore,the free vibration problem of the circular hole plate can be transformed into the free vibration problem of the equivalent rectangular plate with non-uniform thickness.The model is derived from the spectral geometry method(SGM),and the displacement of the plate with circular holes is expanded by the modified Fourier series.Virtual springs are added to the boundary of the plate to simulate the boundary conditions of simply supported and fixed supports.The accuracy of this method is verified by comparison with the finite element calculation results.The relationship between modal numerical solutions of plates with circular holes and boundary conditions and geometry of the plate is studied.展开更多
The stiffness model of the finite element is applied to the Kirchhoff-love closed-form plate buckling;buckling is always in focus in plate assemblages. The useful Eigen-value solutions are unable to separate a square ...The stiffness model of the finite element is applied to the Kirchhoff-love closed-form plate buckling;buckling is always in focus in plate assemblages. The useful Eigen-value solutions are unable to separate a square plate from a much weaker long one in the most commonly-used all-simply supported plate (SSSS), among others. Spring-values of the Kirchhoff-Love plate are sought;once found, displacement-factors can be determined. Comparative </span><span style="font-family:Verdana;">displacements allow </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">an </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">easier and better evaluation of buckling-factors,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> pure-shear, vibration and so are termed “buckling-displacement-factors”. In testing, many plates in mixed boundary conditions are evaluated for displacement</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">assisted buckling-solutions, first. The displacement-factors made from fundamental Eigen-vectors, in a single-pass, are found to be within about one-percent of known elastic values. It is found that the Kirchhoff-Love plate</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">spring and the finite-element spring, demonstrated, here, in the assemblage of beam-elements, are equivalent from the results. In either case</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> stiffness is first assembled, ready for any loading—transverse, buckling, shear, vibration. The simply-supported plate draws the only exact vibration solution, and so, in an additional new effort, all other results are calibrated from it;direct vibration solutions are made for comparison but such results are, hardly, better. In the process, interactive Kirchhoff-Love plate-field-sheets are presented, for design. It is now additionally demanded that the solution Eigen-vector be </span><span style="font-family:Verdana;">developable into a recognizable deflection-factor. A weaker plate cannot possess greater buckling strength, this is a check;to find stiffness the</span><span style="font-family:Verdana;"> deflection-factor must be exact or nearly so. Several examples justify the characteristic buckling displacement-factor as a new tool</span></span></span></span><span style="font-family:Verdana;">.展开更多
对隧道、桥梁结构和沿线建筑而言,浮置板减振性能优异,但其对轨道板及其上部结构的耗能能力有限。针对此问题,将调谐质量粒子阻尼技术应用于轨道交通振动控制领域,提出一种基于调谐质量粒子阻尼器(Tuned Mass Particle Damper,TMPD)的...对隧道、桥梁结构和沿线建筑而言,浮置板减振性能优异,但其对轨道板及其上部结构的耗能能力有限。针对此问题,将调谐质量粒子阻尼技术应用于轨道交通振动控制领域,提出一种基于调谐质量粒子阻尼器(Tuned Mass Particle Damper,TMPD)的耗能型钢弹簧浮置板结构。基于调谐质量阻尼器(Tuned Mass Damper,TMD)及粒子阻尼理论,利用1:1浮置板轨道进行室内试验,通过落轴试验研究调谐质量粒子阻尼器安装前后钢弹簧浮置板轨道动力学特性。研究结果表明:TMPD能显著降低浮置板轨道在固有频率11.7 Hz附近的振动响应,浮置板加速度分频振级损失最大可达11.9 dB;安装TMPD的耗能型钢弹簧浮置板轨道从钢轨到地面的振动衰减最大可达23.6 dB,表明其具有优异的隔振效果;进行Z振级评价分析可得,耗能型钢弹簧浮置板Z振级约降低5 dB,在保证隔振效率基础上,调谐质量粒子阻尼器可提高浮置板轨道的耗能能力。展开更多
Stamping is a critical step in the manufacture of metallic bipolar plates.Typically,residual stress and a spring back effect appear on the bipolar plate after the stamping process,which impacts on the performance and ...Stamping is a critical step in the manufacture of metallic bipolar plates.Typically,residual stress and a spring back effect appear on the bipolar plate after the stamping process,which impacts on the performance and lifetime of the proton exchange membrane fuel cell(PEMFC).The residual stress and spring back behavior which occur as a result of stamping a bipolar plate are investigated in this study.The effects of the punch radius,the die radius,the channel depth,and the clearance between the punch and the die on the residual stress and forming quality of the bipolar plate are examined.The stamping process can be divided into three stages.The high stress area and the middle section residual stress area were selected to study the formation process and to obtain the composition of the residual stress regions.Spring back was mainly related to the position of the fixed end of the sheet and the degree of plastic deformation,and the sheet thickness have increased by 2μm after spring back.Based on the results of finite element analysis,as described by the distribution of residual stress,the formation,the thickness of the middle cross section and the equivalent plastic strain,it was found that all the tool parameters affected the distribution of the residual stress.This research can provide a design reference for the manufacture of metallic bipolar plates based on the stamping process.展开更多
基金Supported by the New-Cooperation Project of Japan Ministry of Economy,Trade and Industry
文摘In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress and spring back of the spiral plate were calculated. Relationships between the spiral pitch to inclination angle of the punch and die, material properties and thickness of the plate were analyzed. A data converter was developed and effectively used in the analysis. The results of FEM analysis and simulation have been applied to design the spiral plate forming machines.
基金supported by the National Natural Science Foundation of China(No.51805341)the Science and Technology Major Project of Ningbo City(No.2021Z098)。
文摘This paper presents a method to study the free vibration of a plate with circular holes.The circular hole is regarded as a virtual small plate in which the mass density and Young's modulus are zero.Therefore,the free vibration problem of the circular hole plate can be transformed into the free vibration problem of the equivalent rectangular plate with non-uniform thickness.The model is derived from the spectral geometry method(SGM),and the displacement of the plate with circular holes is expanded by the modified Fourier series.Virtual springs are added to the boundary of the plate to simulate the boundary conditions of simply supported and fixed supports.The accuracy of this method is verified by comparison with the finite element calculation results.The relationship between modal numerical solutions of plates with circular holes and boundary conditions and geometry of the plate is studied.
文摘The stiffness model of the finite element is applied to the Kirchhoff-love closed-form plate buckling;buckling is always in focus in plate assemblages. The useful Eigen-value solutions are unable to separate a square plate from a much weaker long one in the most commonly-used all-simply supported plate (SSSS), among others. Spring-values of the Kirchhoff-Love plate are sought;once found, displacement-factors can be determined. Comparative </span><span style="font-family:Verdana;">displacements allow </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">an </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">easier and better evaluation of buckling-factors,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> pure-shear, vibration and so are termed “buckling-displacement-factors”. In testing, many plates in mixed boundary conditions are evaluated for displacement</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">assisted buckling-solutions, first. The displacement-factors made from fundamental Eigen-vectors, in a single-pass, are found to be within about one-percent of known elastic values. It is found that the Kirchhoff-Love plate</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">spring and the finite-element spring, demonstrated, here, in the assemblage of beam-elements, are equivalent from the results. In either case</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> stiffness is first assembled, ready for any loading—transverse, buckling, shear, vibration. The simply-supported plate draws the only exact vibration solution, and so, in an additional new effort, all other results are calibrated from it;direct vibration solutions are made for comparison but such results are, hardly, better. In the process, interactive Kirchhoff-Love plate-field-sheets are presented, for design. It is now additionally demanded that the solution Eigen-vector be </span><span style="font-family:Verdana;">developable into a recognizable deflection-factor. A weaker plate cannot possess greater buckling strength, this is a check;to find stiffness the</span><span style="font-family:Verdana;"> deflection-factor must be exact or nearly so. Several examples justify the characteristic buckling displacement-factor as a new tool</span></span></span></span><span style="font-family:Verdana;">.
文摘对隧道、桥梁结构和沿线建筑而言,浮置板减振性能优异,但其对轨道板及其上部结构的耗能能力有限。针对此问题,将调谐质量粒子阻尼技术应用于轨道交通振动控制领域,提出一种基于调谐质量粒子阻尼器(Tuned Mass Particle Damper,TMPD)的耗能型钢弹簧浮置板结构。基于调谐质量阻尼器(Tuned Mass Damper,TMD)及粒子阻尼理论,利用1:1浮置板轨道进行室内试验,通过落轴试验研究调谐质量粒子阻尼器安装前后钢弹簧浮置板轨道动力学特性。研究结果表明:TMPD能显著降低浮置板轨道在固有频率11.7 Hz附近的振动响应,浮置板加速度分频振级损失最大可达11.9 dB;安装TMPD的耗能型钢弹簧浮置板轨道从钢轨到地面的振动衰减最大可达23.6 dB,表明其具有优异的隔振效果;进行Z振级评价分析可得,耗能型钢弹簧浮置板Z振级约降低5 dB,在保证隔振效率基础上,调谐质量粒子阻尼器可提高浮置板轨道的耗能能力。
基金This research was supported by the Sichuan Science and Technology Program(2023YFS0355).
文摘Stamping is a critical step in the manufacture of metallic bipolar plates.Typically,residual stress and a spring back effect appear on the bipolar plate after the stamping process,which impacts on the performance and lifetime of the proton exchange membrane fuel cell(PEMFC).The residual stress and spring back behavior which occur as a result of stamping a bipolar plate are investigated in this study.The effects of the punch radius,the die radius,the channel depth,and the clearance between the punch and the die on the residual stress and forming quality of the bipolar plate are examined.The stamping process can be divided into three stages.The high stress area and the middle section residual stress area were selected to study the formation process and to obtain the composition of the residual stress regions.Spring back was mainly related to the position of the fixed end of the sheet and the degree of plastic deformation,and the sheet thickness have increased by 2μm after spring back.Based on the results of finite element analysis,as described by the distribution of residual stress,the formation,the thickness of the middle cross section and the equivalent plastic strain,it was found that all the tool parameters affected the distribution of the residual stress.This research can provide a design reference for the manufacture of metallic bipolar plates based on the stamping process.
